<template>
  <div class="box" ref="box">
    <div class="left">
      <!--左侧div内容-->
      <slot name="left"></slot>
    </div>
    <div class="resize" title="">

    </div>
    <div class="mid">
      <slot name="right"></slot>

      <!--右侧div内容-->
    </div>
  </div>
</template>

<script>
  export default {
    name: 'ResizePanel',
    props: {

    },
    computed: {

    },
    watch: {

    },
    mounted() {
      this.dragControllerDiv();
    },
    beforeDestroy() {

    },
    methods: {
      dragControllerDiv() {
        var resize = document.getElementsByClassName('resize');
        var left = document.getElementsByClassName('left');
        var mid = document.getElementsByClassName('mid');
        var box = document.getElementsByClassName('box');
        for (let i = 0; i < resize.length; i++) {
          // 鼠标按下事件
          resize[i].onmousedown = function(e) {
            //颜色改变提醒
            resize[i].style.background = '#818181';
            var startX = e.clientX;
            resize[i].left = resize[i].offsetLeft;
            // 鼠标拖动事件
            document.onmousemove = function(e) {
              var endX = e.clientX;
              var moveLen = resize[i].left + (endX - startX); // （endx-startx）=移动的距离。resize[i].left+移动的距离=左边区域最后的宽度
              var maxT = box[i].clientWidth - resize[i].offsetWidth; // 容器宽度 - 左边区域的宽度 = 右边区域的宽度

              if (moveLen < 250) moveLen = 250; // 左边区域的最小宽度为32px
              if (moveLen > maxT - 250) moveLen = maxT - 250; //右边区域最小宽度为150px

              resize[i].style.left = moveLen; // 设置左侧区域的宽度

              for (let j = 0; j < left.length; j++) {
                left[j].style.width = moveLen + 'px';
                mid[j].style.width = (box[i].clientWidth - moveLen - 5) + 'px';
              }
            };
            // 鼠标松开事件
            document.onmouseup = function(evt) {
              //颜色恢复
              resize[i].style.background = '#d6d6d6';
              document.onmousemove = null;
              document.onmouseup = null;
              resize[i].releaseCapture && resize[i].releaseCapture(); //当你不在需要继续获得鼠标消息就要应该调用ReleaseCapture()释放掉
            };
            resize[i].setCapture && resize[i].setCapture(); //该函数在属于当前线程的指定窗口里设置鼠标捕获
            return false;
          };
        }
      },

    }
  }
</script>

<style lang="scss" scoped>
  /* 拖拽相关样式 */
  /*包围div样式*/
  .box {
    width: 100%;
    height: 100%;
    overflow: hidden;
  }

  /*左侧div样式*/
  .left {
    width: 250px;
    /*左侧初始化宽度*/
    height: 100%;
    // padding-right: 5px;
    background: #FFFFFF;
    float: left;
  }

  /*拖拽区div样式*/
  .resize {
    cursor: col-resize;
    float: left;
    position: relative;
    background-color: #d6d6d6;
    // border-radius: 5px;
    width: 5px;
    height: 100%;
    /*z-index: 99999;*/
    font-size: 32px;
    color: white;
  }

  /*拖拽区鼠标悬停样式*/
  .resize:hover {
    color: #444444;
  }

  /*右侧div'样式*/
  .mid {
    float: left;
    width: calc(100% - 255px);
    /*右侧初始化宽度*/
    height: 100%;
    background: #fff;
    padding: 10px;

  }
</style>
